strati.ch - Lessico lithostratigrafico della Svizzera

Rappresentazione e statuto

Revisione: Gouffon Yves (Editor) (2024) : Tectonic Map of Switzerland 1:500000, Explanatory notes. Federal Office of Topography swisstopo, Wabern

p.71: Between Thunersee and Vierwaldstättersee, the Upper Helvetic Drusberg Nappe contains a large synform occupied by the tectonically higher Habkern Mélange Zone overlain by the Schlieren Nappe. This nappe only consists of Cretaceous – Paleogene flysch very similar to the Voirons and Gurnigel flysches in the Prealps (§ 6.1.1.1). Further east, up to the Walensee, a similar flysch forms the Wägital Nappe, which is located at the front of the Drusberg Nappe and surrounded by the Iberg Mélange and the Internal Einsiedeln Slices of the Upper Helvetic. As the Schlieren and Wägital nappes are overlain by Middle Penninic klippen, they are considered to be Lower Penninic. The paleogeographical allocation of all these nappes is a matter of debate. While Winkler (1983) envisaged the origin of the Schlieren Flysch in the Piemonte-Liguria Ocean, these units were considered by others (Trümpy 2006, Pfiffner 2014, Ragusa et al. 2017) to be of Valaisan origin.